Viessmann · Vitocrossal 200 (CM2, GW6B)
Viessmann Vitocrossal 200 CM2-311
The Vitocrossal 200 CM2-311 is the largest model of the small CM2 (GW6B) chassis: 222 to 1112 MBH natural-gas input (65 to 326 kW) at 95% combustion efficiency, 5:1 turndown, in a 792 lb (359 kg) unit.
Key figures
- Max input
- 1,112 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- 222 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Viessmann Vitocrossal 200 CM2-311 in practice
The CM2-311 tops the small size range of the Vitocrossal 200 CM2 series before the line steps to the CM2-400's much larger chassis. Its natural-gas input prints from 222,000 to 1,112,000 BTU (65 to 326 kW) — input beyond one million BTU in the 792 lb (359 kg) small-chassis cabinet.
With the CM2-186 and CM2-246 it is covered by the 186–311 service instructions (doc 5584 109 - 16, 05/2021), and it prints the small range's 95% combustion efficiency and 5:1 turndown ratio. At 792 lb it is 33 lb heavier than the CM2-246.
Series features include the Inox-Crossal stainless steel heat exchanger, pre-mix cylinder burner, GW6B control with cascade control of up to eight boilers, common venting of up to four boilers, altitude operation to 10,000 ft with electronic adjustment and no dedicated boiler pump required.
Best suited to
- Commercial loads up to about 1112 MBH that fit the CM2 small chassis
- Plants wanting more than 1000 MBH of input before stepping to the large CM2 cabinet
- Multi-boiler rooms standardizing on the 186–311 manual range
Applicability and support
- Model number
- CM2-311
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Viessmann. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, minimum (natural gas) | 222 MBH | 222,000 BTU (65 kW), per the product page |
| Input, maximum (natural gas) | 1,112 MBH | 1,112,000 BTU (326 kW), per the product page |
| Efficiency | ||
| Combustion efficiency | 95 % | Per the product-page efficiency row. |
| Physical and connections | ||
| Weight | 792 lb | 359 kg |
| Operating limits and other | ||
| Turndown ratio | 5:1 | Per the product page. |
Manuals
Alerts documented for this model
Frequently asked questions
What is the firing range of the CM2-311?
Natural-gas input runs 222,000 to 1,112,000 BTU (65 to 326 kW) per the product page — the top of the small CM2 range.
When should I step from the CM2-311 to the CM2-400?
When the load exceeds about 1112 MBH: the CM2-400 moves to the large chassis at 1495 lb (678 kg) and prints 95.1% combustion efficiency, with its own service manual (doc 5546 489 - 15).
What efficiency does the CM2-311 print?
95% combustion efficiency per the product page, as printed for the CM2-186, CM2-246 and CM2-311.
Questions about the Viessmann Vitocrossal 200 CM2-311?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Compare and explore
- Viessmann Vitocrossal 200 CM2-246 vs CM2-311Comparison
- Viessmann Vitocrossal 200 CM2-311 vs CM2-400Comparison
- Viessmann Vitocrossal 200 CM2-186Same series
- Viessmann Vitocrossal 200 CM2-246Same series
- Viessmann Vitocrossal 200 CM2-400Same series
- Viessmann Vitocrossal 200 CM2-500Same series
- Viessmann Vitocrossal 200 CM2-620Same series
- Vitocrossal 200 (CM2, GW6B) series hub
- Buying guide
Sources and verification
- Viessmann Canada — Vitocrossal 200 CM2 product page · accessed September 9, 2026
- Service Instructions — Vitocrossal 200 CM2 Series 186 to 311, doc 5584 109 - 16 · 5584 109 - 16 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.